Nine cowsheds were used, the differences between each cowshed are orientation (east-west or north-south), cooling (with or without), and height (3 m, 5 m or 8 m height). Dry-bulb temperature, relative humidity, ...Nine cowsheds were used, the differences between each cowshed are orientation (east-west or north-south), cooling (with or without), and height (3 m, 5 m or 8 m height). Dry-bulb temperature, relative humidity, dew point, shaded area, air velocity, and maximum temperature were measured beneath each shed. The temperature-humidity index (THI) and the shading efficiency were calculated for each cowshed. The trials were conducted using 180 lactating Holstein Friesian cows; twenty cows housed beneath each shade structure. Measurements performed on cows were respiration rate, skin temperature, and rectal temperature; moreover, the milk produced by each cow was recorded, and the feed intake. High air velocities were recorded under high shade structures which enhance the aeration; consequently, maximum temperatures, and THI recorded beneath high sheds were less than those recorded beneath low sheds; also, skin temperatures, and respiration rates for cows housed under high sheds were less than those measured for animals housed under low sheds(differences were found to be significant). Thereby, increasing shed height enhances dairy cows' microclimate under Egyptian conditions (hot climate); consequently, the milk production increases. The best orientation is the east-west orientation, which is preferable for hot climates. The exploitation of cooling has significant effect on microclimate, cooling enhances the ambient environment and provides comfortable zone for dairy cows within which cows reach high production levels.展开更多
Hot rolled strip requires diverse and flexible control of cooling path in order to take full advantages of strengthening mechanisms such as fine grain strengthening, precipitation strengthening, and transformation str...Hot rolled strip requires diverse and flexible control of cooling path in order to take full advantages of strengthening mechanisms such as fine grain strengthening, precipitation strengthening, and transformation strengthening, adapting to the development of advanced steel materials and the requirement of reduction-manufacturing. Ultra fast cooling can achieve a great range of cooling rate, which provides the means that the hardened austenite obtained in high temperature region can keep at different dynamic transformation temperatures. Meanwhile, through the rational allocation of the UFC (ultra fast cooling) and LFC (laminar flow cooling), more flexible cooling path control and cooling strategy of hot rolled strip are obtained. Temperature distribution and control strategies under different cooling paths based on UFC are investigated. The process control temperature can be limited within 18 ℃, and the mechanical properties of the steels get a great leap forward due to the cooling paths and strategies, which can decrease costs and create great economic benefits for the iron and steel enterprises.展开更多
The harsh environment in tunnels with high geothermal temperatures and humidity can adversely impact machinery,personnel,and construction.The main causes of specific problems are the unknown mechanisms of local geothe...The harsh environment in tunnels with high geothermal temperatures and humidity can adversely impact machinery,personnel,and construction.The main causes of specific problems are the unknown mechanisms of local geothermal formation,inappropriate temperature control measures,and insufficient systematic safeguards.In this study,three work sections relating to a high geothermal tunnel are:the tunnel face,middle-of-tunnel section,and outside-oftunnel section.A cooling strategy is proposed to offer technical support in achieving comprehensive cooling,overall as well as for each of the sections.First,a comprehensive geological survey explores the mechanism and exact location of the heat source.Secondly,grouting and centralized drainage measures are used to control the heat release of hot water.Enhanced ventilation,ice chillers and other applicable measures are used to control the ambient temperature.Finally,a monitoring and early warning system is established to prevent accidents.This cooling strategy has been applied in the field with good results.展开更多
On the basis of the finite difference method, the factors affecting the temperature distribution along the thickness of plate during cooling process were analyzed, which include transformation heat, coefficient of hea...On the basis of the finite difference method, the factors affecting the temperature distribution along the thickness of plate during cooling process were analyzed, which include transformation heat, coefficient of heat conduction, specific heat, carbon content, cooling time, plate thickness, and unit of water flow volume. To ensure the homogenous temperature distribution along the thickness of plate, some cooling strategies, such as interval cooling, stepped cooling, and unsymmetrical cooling of upper and lower surfaces, were applied online. The online results showed that the cooling strategies can improve the temperature homogeneity greatly and the finite difference method can correctly simulate the cooling process.展开更多
It is well known that the passive strategies applying in traditional buildings respond satisfactory to climatic requirements and succeed to provide maximum indoor comfort with minimum energy consumption.From this poin...It is well known that the passive strategies applying in traditional buildings respond satisfactory to climatic requirements and succeed to provide maximum indoor comfort with minimum energy consumption.From this point of view,it is interesting to quantitatively assess the effectiveness of the vernacular strategies to improve the environmental performance of the building's envelope under desert climate conditions.The research tries to address this issue and was undertaken in southern Algeria where a very hot and arid climate prevails.The effect of some selected passive cooling strategies on enhancing the building's envelope climate performance was examined.These strategies are inspired from the local vernacular architecture,and they are expected to provide satisfactory indoor thermal comfort for users and to reduce the energy cooling demand from residential buildings.Applying field and computational investigations,two existing residential buildings were tested:a typical residential unit and a contemporary vernacular(neo-vernacular)building.In the latter,climate responsive strategies inspired from vernacular architecture were applied.A comparison based on site measurements was carried out on the two selected buildings which differ from their envelope design properties and components.展开更多
文摘Nine cowsheds were used, the differences between each cowshed are orientation (east-west or north-south), cooling (with or without), and height (3 m, 5 m or 8 m height). Dry-bulb temperature, relative humidity, dew point, shaded area, air velocity, and maximum temperature were measured beneath each shed. The temperature-humidity index (THI) and the shading efficiency were calculated for each cowshed. The trials were conducted using 180 lactating Holstein Friesian cows; twenty cows housed beneath each shade structure. Measurements performed on cows were respiration rate, skin temperature, and rectal temperature; moreover, the milk produced by each cow was recorded, and the feed intake. High air velocities were recorded under high shade structures which enhance the aeration; consequently, maximum temperatures, and THI recorded beneath high sheds were less than those recorded beneath low sheds; also, skin temperatures, and respiration rates for cows housed under high sheds were less than those measured for animals housed under low sheds(differences were found to be significant). Thereby, increasing shed height enhances dairy cows' microclimate under Egyptian conditions (hot climate); consequently, the milk production increases. The best orientation is the east-west orientation, which is preferable for hot climates. The exploitation of cooling has significant effect on microclimate, cooling enhances the ambient environment and provides comfortable zone for dairy cows within which cows reach high production levels.
基金Project(2006BAE03A08)supported by the National Key Technology R&D Program of China
文摘Hot rolled strip requires diverse and flexible control of cooling path in order to take full advantages of strengthening mechanisms such as fine grain strengthening, precipitation strengthening, and transformation strengthening, adapting to the development of advanced steel materials and the requirement of reduction-manufacturing. Ultra fast cooling can achieve a great range of cooling rate, which provides the means that the hardened austenite obtained in high temperature region can keep at different dynamic transformation temperatures. Meanwhile, through the rational allocation of the UFC (ultra fast cooling) and LFC (laminar flow cooling), more flexible cooling path control and cooling strategy of hot rolled strip are obtained. Temperature distribution and control strategies under different cooling paths based on UFC are investigated. The process control temperature can be limited within 18 ℃, and the mechanical properties of the steels get a great leap forward due to the cooling paths and strategies, which can decrease costs and create great economic benefits for the iron and steel enterprises.
基金supported by the National Natural Science Foundation of China(Grant Nos.51878567 and 51878568).
文摘The harsh environment in tunnels with high geothermal temperatures and humidity can adversely impact machinery,personnel,and construction.The main causes of specific problems are the unknown mechanisms of local geothermal formation,inappropriate temperature control measures,and insufficient systematic safeguards.In this study,three work sections relating to a high geothermal tunnel are:the tunnel face,middle-of-tunnel section,and outside-oftunnel section.A cooling strategy is proposed to offer technical support in achieving comprehensive cooling,overall as well as for each of the sections.First,a comprehensive geological survey explores the mechanism and exact location of the heat source.Secondly,grouting and centralized drainage measures are used to control the heat release of hot water.Enhanced ventilation,ice chillers and other applicable measures are used to control the ambient temperature.Finally,a monitoring and early warning system is established to prevent accidents.This cooling strategy has been applied in the field with good results.
基金Item Sponsored by National Natural Science Foundation of China (50634030)National Key Technology Research and Development Program of China (2006BAE03A08)
文摘On the basis of the finite difference method, the factors affecting the temperature distribution along the thickness of plate during cooling process were analyzed, which include transformation heat, coefficient of heat conduction, specific heat, carbon content, cooling time, plate thickness, and unit of water flow volume. To ensure the homogenous temperature distribution along the thickness of plate, some cooling strategies, such as interval cooling, stepped cooling, and unsymmetrical cooling of upper and lower surfaces, were applied online. The online results showed that the cooling strategies can improve the temperature homogeneity greatly and the finite difference method can correctly simulate the cooling process.
文摘It is well known that the passive strategies applying in traditional buildings respond satisfactory to climatic requirements and succeed to provide maximum indoor comfort with minimum energy consumption.From this point of view,it is interesting to quantitatively assess the effectiveness of the vernacular strategies to improve the environmental performance of the building's envelope under desert climate conditions.The research tries to address this issue and was undertaken in southern Algeria where a very hot and arid climate prevails.The effect of some selected passive cooling strategies on enhancing the building's envelope climate performance was examined.These strategies are inspired from the local vernacular architecture,and they are expected to provide satisfactory indoor thermal comfort for users and to reduce the energy cooling demand from residential buildings.Applying field and computational investigations,two existing residential buildings were tested:a typical residential unit and a contemporary vernacular(neo-vernacular)building.In the latter,climate responsive strategies inspired from vernacular architecture were applied.A comparison based on site measurements was carried out on the two selected buildings which differ from their envelope design properties and components.